[1] Univ Nacl Tucuman, Fac Med, LINT, RA-4000 San Miguel De Tucuman, Argentina
[2] FLENI, Dept Neurocirug, RA-1625 Buenos Aires, Argentina
[3] Hosp Virgen Rocio, Seville 41013, Spain
[4] Med Univ Vienna, Endoscop Lab Anat Ctr, A-1090 Vienna, Austria
[5] Univ Cape Town, Dept Neurosurg, ZA-7701 Cape Town, South Africa
[6] Univ Napoli Federico II, Dept Neurosci Reprod & Odontostomatol Sci, Div Neurosurg, I-80131 Naples, Italy